One advantage I see is that most important mail (ie business mail) would generally have few spelling errors, although the exact rate would no doubt vary depending on the business you are in.

Personal mail is likely to contain a few lazy errors and 'cute' spellings, but I would imagine in a fairly short space of time it would be possible to 'teach' the dictionary and/or develop rules to reduce the false positives. For example the 'English' dictionary could comprise English and American spellings, common mis-spellings, and modern abbreviations for example.

If we were going to get clever about it, we could also implement a 'hot list' of words that spammers try to mis-spell (eg viagra, mortgage) so the filter could assign a higher score if it thinks the mis-spelled word is close to a hotlist word. This hotlist could even update periodically / submit itself to a master database.

Any words containing a number should probably be given a higher score, and perhaps the same mis-spelling appearing more than once should not receive multiple scores (for example a brand name, industry jargon or model number that may be repeated).

Thanks, that is a neat idea. There may be some obstacles in terms of computer resources (there's already quite a lot of activity whenever a single messages is checked for spam, so initiating the spell-check engine may slow down the process), I'll add it to our wishlist!

Hi, nice idea... but don't forget that people like me (and many others in Europe) receive messages in various languages. We should be able to select more than just one dictionary (e.g. German, French and English). Sometimes, even a single email message comprises several languages, e.g. a lot of admin messages from airlines, ISPs, etc. contain the text in up to 5 languages. I am living in Switzerland (4 national languages & English), but I guess this is also valid for other nations like Canada (French and English) as well.